The embodiments described herein relate generally to a circuit protection device and, more particularly, to an apparatus for use in monitoring a charge status of a capacitor of a circuit protection device.
Known electric distribution circuits and switchgear generally have conductors that are separated by insulation, such as air, or gas or solid dielectrics. However, if the conductors are positioned too closely together, or if a voltage between the conductors exceeds the insulative properties of the insulation between the conductors, an arc can occur. For example, the insulation between the conductors can become ionized, which makes the insulation conductive and enables formation of an arc flash.
An arc flash includes a rapid release of energy due to a fault between two phase conductors, between a phase conductor and a neutral conductor, or between a phase conductor and a ground point. Arc flash temperatures can reach or exceed 20,000° C., which can vaporize the conductors and adjacent equipment. Moreover, an arc flash can release significant energy in the form of not only heat, but also intense light, pressure waves, and/or sound waves, sufficient to damage the conductors and adjacent equipment. However, the current level of a fault that generates an arc flash is generally less than the current level of a short circuit, such that a circuit breaker generally does not trip or may exhibit a delayed trip unless the circuit breaker is specifically designed to handle an arc fault condition.
At least some known circuit protection devices include one or more high voltage and high energy capacitors for use in initiating a secondary arc flash within an enclosure that is designed to safely contain the energy released by the secondary arc flash. These capacitors can be used to provide energy to an ablative plasma gun that releases plasma into a gap between a plurality of electrodes to facilitate formation of the secondary arc flash. Similarly, at least some known circuit protection devices include one or more high voltage and high energy capacitors for use in interrupting current flow through the circuit protection device by causing separation of conductive contact arms. At least some known capacitors experience failure or degradation in performance over time due to heat generated within the circuit protection device, for example. However, it is difficult to observe the charge status of these capacitors. Unracking these circuit protection devices while the capacitors are charged or are charging can lead to severe electrical shocks or burns if an operator were to come into contact with the capacitors. Accordingly, it is desirable to provide a means of monitoring and indicating the charge status of the capacitor and/or a means to alter the charge status of the capacitor.